Composition, Physicochemical Properties, and Uses of Acorn Starch

Abstract

The major component of acorn is starch, which may amount up to 55% of the dry weight. Lack of systematic knowledge on acorn starch greatly hinders the further development of acorns as sustainable crops. This review aims to summarize the current knowledge of the isolation, chemical composition, physicochemical properties, and uses of acorn starches and to provide future research directions. The amylose content of the acorn starches is reported to vary in the range of 20–39%. Moisture content, lipid, ash, and protein contents of the acorn starches have been reported varying from 2.20 to 15.50%, 0.23 to 2.64%, 0.01 to 1.41%, and 0.01 to 6.7%, respectively. Thermal and pasting properties that have usually been determined using differential scanning calorimeter (DSC) and rapid viscoanalyzer (RVA) are also discussed in this article. Acorn starch has great potential for various food and nonfood applications due to the unique structural and functional features.

Physicochemical, Structural, Thermal and Rheological Properties of Flour and Starch Isolated from Avocado Seeds of Landrace and Hass Cultivars

“…The starches absorbed more energy in the gelatinization process to break the crystalline arrangement of their granules [55]. These results contradict those found by Hoover and Sosulski [58], who mention that, the higher the crystallinity, the greater the energy required for gelatinization to occur, due to a higher order of molecules (see index and percentage of crystallinity in Table 2). This behavior can be due to the partial fusion of the crystals of the ordered region, since the low values of enthalpies in flour may be the consequence of a possible heterogeneity of the ordered structures within the granules [55].…”

“…These results suggest a higher degree of association between the components in the starches of avocado cv. Hass and landrace [58].…”

“…The variation in the functional properties of starches may be due to the degree of coupling of the hydroxyl groups to form hydrogen bonds between the starch chains. In addition, the increase in SP and WAI are associated with increased leaching and solubility of amylose due to the loss of the crystal structure of starches [58].…”

Comparative Study of the Physiochemical Composition and Techno-Functional Properties of Two Extracted Acorn Starches

“…Irinislimane and Belhaneche Ben semr [18] and Correia et al [12] isolated starch from Quercus Suber L. acorns and observed a starch yield accounting 21% and 31.4%, respectively. The starch content in potatoes, tubers and roots are reported to vary from 75 to 80% and 75.4 to 77.4% [5], respectively.…”

“…Traditionally, acorns were used in the human diet, generally as flour for bread production, or as a coffee substitute beverage (after a roasting process) [4]. Recently, acorn fruit flour was included in many other food preparations such as pasta, biscuits, hot beverages, cakes, and cookies [5]. Among all the nutrients present in acorn fruit, starch was the predominant component with content ranging from 31 to 55% [1].…”